Days are getting longer, the snow cover is receding, and look what it exposed all around the base of the bird feeding station!
They circle the area!
And in front of each hole, there is a pile of empty sunflower seed shells.
A little closer view! Regretfully, I was never quite quick enough to capture any of the voles as they darted in and out of the safety of their little holes.
Here in New England, voles, mice, and shrews live in and navigate through tunnels under the snow cover. This area is called the "subnivian space", an extensive, continuous air space at ground level between the snow and the earth. Temperatures maintain a fairly even 32 degrees F.
In Bernd Heinrich's book, Winter World, he explains that near the top of any snowpack, the snow gets denser as the crystals bond together. But, closer to the ground, where it is warmer than at the surface, water vapor from disintergrating snow crystals migrates upward and recondenses, freezing onto the upper snow pack crystals, and creating this subnivian space.
Young trees are very susceptible to the hungry winter appetites of these little critters. They will chew the young, tender bark right off the bottom of the trunks, all the way up to the top of the snow mark. It is enough to damage and kill the tree. Trees planted purposefully will require protection!
Here's a picture of a picture sketched by Bernd to illustrate the activity described above.
Note the grass nest to the left. Mice, voles, and shrews will breed very early in the spring when the sun is bright enough to penetrate the frozen ice crystals overhead. Voles, especially, are very prolific!
But with the help of owls, foxes, coyotes, and weasels, their population remains manageable.
Great grey owls can hear the movement clear through the snow cover from 30 meters away (that's well over 90 feet!), and using their balled up feet, will crash right through the snow to catch their prey. Foxes and coyotes located voles by sound, as well, and dig through the snow for their tasty treat.
One final, interesting note - when the snow cover totally recedes and the voles vacate their fully exposed grass nests, they are often taken over by bumblebee queens that are starting new colonies.
There is just so much going on in our natural world. How could one not be curious?
For more Nature Notes/Signs of the Season,
please click HERE!
Thank you Michelle at Rambling Woods for
hostessing such a delightful meme!